A complete representation of all available relevant documents can be critical to a topic analysis, such as a systematic review or a meta-analysis. One way to find relevant documents is a keyword-based search. However, keyword-based searches often do not provide a complete representation of relevant documents because the terminology for key concepts, variables and outcomes often differ among documents. To provide a more complete representation, keyword-based searches are often complimented by manual screening of the citation information of retrieved documents. Many documents do not consistently cite related earlier work and therefore searching based on direct citations can be unreliable. Thus, determining relevant documents can be challenging and time consuming.